Question: What do the following two equations represent? $-5x+y = 1$ $-3x-15y = 1$
Solution: Putting the first equation in $y = mx + b$ form gives: $-5x+y = 1$ $y = 5x+1$ Putting the second equation in $y = mx + b$ form gives: $-3x-15y = 1$ $-15y = 3x+1$ $y = -\dfrac{1}{5}x - \dfrac{1}{15}$ The slopes are negative inverses of each other, so the lines are perpendicular.